Liberty Media Chairman John Malone told CNNfn the proposal had been made, and that Liberty would consider joining the bid if such a scenario develops.

The broadband unit has been a loss leader for AT&T ever since the company purchased Malone’s TCI cable operations in 1998. Comcast (CMCSK: news, chart, profile) made a bid for the systems earlier this year, but AT&T turned that proposal down.

Several other companies are considered to be potential suitors for the cable unit, among them Walt Disney Co. (DIS: news, chart, profile) and Cox Communications (COX.: news, chart, profile).

Disney shares closed 38 cents lower at $24.11, while Cox shed 93 cents at $39.10. David B. Wilkerson is a reporter for CBS.MarketWatch.com in San Francisco.